In the related art, the speed of a motor used for carrying a sheet is set considering the dimensional tolerance of a component used for carrying the sheet. In addition, in the speed setting, an amount of deflection of the sheet should not be extremely large and should not be extremely small considering the length of the sheet. However, as the reduction of the size of the image forming apparatus progresses, a space for folding the sheet is reduced, and thus, a rotational speed of each roller should be more precisely set. Meanwhile, since a diameter of the roller is reduced, a variation in rotational speed due to a dimensional tolerance of the component significantly increases. As a result, the actual rotational speed of the roller is far from a set value of the motor speed related to ideal sheet carrying, and there is a resultant disadvantageous case where image defects occur.